aosp12/external/skia/docs/examples/Canvas_MakeRasterDirect.cpp

29 lines
1.5 KiB
C++

// Copyright 2019 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"
// HASH=525285073aae7e53eb8f454a398f880c
REG_FIDDLE(Canvas_MakeRasterDirect, 256, 256, true, 0) {
void draw(SkCanvas* ) {
SkImageInfo info = SkImageInfo::MakeN32Premul(3, 3); // device aligned, 32 bpp, Premultiplied
const size_t minRowBytes = info.minRowBytes(); // bytes used by one bitmap row
const size_t size = info.computeMinByteSize(); // bytes used by all rows
SkAutoTMalloc<SkPMColor> storage(size); // allocate storage for pixels
SkPMColor* pixels = storage.get(); // get pointer to allocated storage
// create a SkCanvas backed by a raster device, and delete it when the
// function goes out of scope.
std::unique_ptr<SkCanvas> canvas = SkCanvas::MakeRasterDirect(info, pixels, minRowBytes);
canvas->clear(SK_ColorWHITE); // white is Unpremultiplied, in ARGB order
canvas->flush(); // ensure that pixels are cleared
SkPMColor pmWhite = pixels[0]; // the Premultiplied format may vary
SkPaint paint; // by default, draws black
canvas->drawPoint(1, 1, paint); // draw in the center
canvas->flush(); // ensure that point was drawn
for (int y = 0; y < info.height(); ++y) {
for (int x = 0; x < info.width(); ++x) {
SkDebugf("%c", *pixels++ == pmWhite ? '-' : 'x');
}
SkDebugf("\n");
}
}
} // END FIDDLE